Her curves endeared her to the size 14 women of the world and despite Blow's blunt advice - "No more chips and puddings for you'' - she became fatter, not thinner, during the early stages of her modelling career.

Instead of cooking, she ate in restaurants. When she was at home, she ordered enough takeaway for two.

But during her twenties she slimmed down to a conventional model shape, losing her puppy fat.

In 2000, Dahl achieved a degree of notoriety when she was cast her in an advertisement for the Yves Saint-Laurent perfume brand Opium.

The ad featured a photograph of her posing nude on black satin.

It was removed from UK billboards after complaints were made to the Advertising Standards Authority.

Dahl, who was the inspiration for the character Sophie in her grandfather's story The BFG, has since written a number of books and has recently branched out into cookery writing and presenting.

In 2010, her six-part cookery series entitled The Delicious Miss Dahl, which Dahl wrote and presented, was broadcast on BBC 2.

She also wrote and presented a television programme about the Victorian cook, Isabella Beeton which was transmitted on BBC2 last year.

She is patron of the Roald Dahl Museum and Story Centre in Great Missenden, Buckinghamshire, which preserves her grandfather's legacy.

The charity has recently been criticised for appealing to the public for money to renovate the author's writing shed in the garden of the family home.

She is married to the musician Jamie Cullum and they have a daughter named Lyra.